CVE-2026-64286: Linux kernel · KVM: arm64: Clear __hyp_running_vcpu when flushing the pKVM hyp vCPU
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 8.2 High · fixed in e8042f6e1d7befb2fb6b10a75918642bcd0acf9a : patch Linux kernel soon.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in e8042f6e1d7befb2fb6b10a75918642bcd0acf9a, dfaef40d8a1533940fc1af788d70fce07362b4ce, d4f4d61715d1061ba83b88196a3605662be30750 +2
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 25 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in– |
Description
In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: Clear __hyp_running_vcpu when flushing the pKVM hyp vCPU flush_hyp_vcpu() copies the host vCPU context into the hyp's private vCPU on every run. ctxt_to_vcpu() expects a guest context to have a NULL __hyp_running_vcpu, which is only ever set on the host context, so that it resolves the vCPU via container_of(). While this is generally the case, flush_hyp_vcpu() copies the context verbatim and does not enforce this, so a value provided by the host is dereferenced at EL2 (host -> EL2). Fix by clearing __hyp_running_vcpu after the copy.
References
- git.kernel.org/stable/c/477145860dba4c30f0b4e36f02f4c5291c1c888b (opens in a new tab)
- git.kernel.org/stable/c/dfaef40d8a1533940fc1af788d70fce07362b4ce (opens in a new tab)
- git.kernel.org/stable/c/6bea2f8becdb20d34378493c3b77a9b9cf8c6cfa (opens in a new tab)
- git.kernel.org/stable/c/d4f4d61715d1061ba83b88196a3605662be30750 (opens in a new tab)
- git.kernel.org/stable/c/e8042f6e1d7befb2fb6b10a75918642bcd0acf9a (opens in a new tab)